If you have one of the conditions listed below, you could also contact your care team instead of your GP.

Causes of pyoderma gangrenosum

The exact cause of pyoderma gangrenosum is not understood, but it's thought to be a reaction to a disease or illness. However, many people have no related condition and there's no obvious reason for it.

The skin reaction isn't passed down to children from their parents through genes. It's also not contagious so can't be transferred from or to another person.

The reaction may sometimes be triggered by minor skin damage or an injury – for example, it may develop around a wound, a needle prick, a biopsy or an insect bite.

When the affected skin tissue is tested, it usually has a high concentration of neutrophils (white blood cells involved in inflammation). This means pyoderma gangrenosum may be related to overactivity of the immune system.

People at risk of pyoderma gangrenosum

People with the following health conditions are most likely to develop pyoderma gangrenosum, even if the condition is mild or well controlled: